[redis] Add support for Redis execute tool

### Prerequisites

- [x] Search the [current open issues](https://github.com/googleapis/genai-toolbox/issues)

### What are you trying to do that currently feels hard or impossible?

Currently, we need to define a series of preset commands to operate Redis, which is troublesome. I believe a more flexible usage would be more convenient, only requiring a single client for execution

### Suggested Solution(s)

like mysql-sql and mysql-execute-sql

### Alternatives Considered

_No response_

### Additional Details

_No response_